1. Field of Invention
The present invention relates to a series of novel ester containing phosphobetaine compounds which are exceptional surface active agents that provide outstanding foam and are very mild to the hair and skin, and are not persistent in the aquatic environment. The compounds, because they contain a pendant ionizable phosphate group and a quaternary amine compound are amphoteric surfactants that is they contain both a positive and negative charge in the same molecule. This combination of properties makes these polymers ideally suited for use in personal care applications.
The compounds of the present invention are based upon raw materials which are prepared by the reaction of a polyoxyalkylene containing ester with a phosphating reagent then by reaction of this intermediate with an epoxy quat intermediate.
The technology used to produce the phosphobetaine compounds of the present invention is very flexible and allows us to prepare performance tailored molecules for specific applications.
2. Description f the Arts and Practices
Fatty phosphobetaine compounds have been known since 1974. There are several patents, which have issued on this topic.
U.S. Pat. Nos. 3,856,893 and 3,928,509 both issued to Diery disclose the basic technology used to make phosphobetaine compounds.
Later, amido and imidazoline based phosphobetaine compounds were patented in U.S. Pat. No. 4,209,449 issued in 1980 to Mayhew and O""Lenick. This patent teaches that phosphate quats can be prepared by the reaction of a phosphate salt, three equivalents of epichlorohydrin and in a subsequent step, three equivalents of a tertiary amine.
U.S. Pat. No. 4,215,064 issued in 1980 to Lindemann et al teaches the basic technology that is used for the preparation of amido and imidazoline based phosphobetaine compounds. These compounds can be prepared by the reaction of a phosphate salt, one equivalent of epichlorohydrin and one equivalent of a tertiary amine.
U.S. Pat. No. 4,243,602 issued in 1981 to O""Lenick and Mayhew teaches the basic technology that is used for the preparation of phosphobetaine compounds based upon phosphorous acid salts. These compounds can be prepared by the reaction of a phosphorous acid salt, one equivalent of epichlorohydrin and one equivalent of a tertiary amine.
U.S. Pat. No. 4,261,911 issued in 1981 to Lindemann et al teaches the utilization of phosphobetaine compounds based upon phosphorous acid. These compounds are useful as surfactants.
U.S. Pat. No. 4,283,542 issued in 1981 to O""Lenick and Mayhew teaches the process technology used for the preparation of phosphobetaine compounds. These compounds can be prepared by the reaction of a phosphate salt, one equivalent of epichlorohydrin and one equivalent of a tertiary amine.
U.S. Pat. No. 4,336,386 issued in 1982 to O""Lenick and Mayhew teaches the technology for the preparation of imidazoline-derived phosphobetaine compounds based upon phosphorous acid salts. These compounds can be prepared by the reaction of a phosphorous acid salt, one equivalent of epichlorohydrin and one equivalent of an imidazoline.
U.S. Pat. No. 4,503,002, which is related to U.S. Pat. No. 4,209,449 issued in 1985 to Mayhew and O""Lenick teach that phosphate quats can be prepared by the reaction of a phosphate salt, three equivalents of epichlorohydrin and three equivalents of a tertiary amine.
U.S. Pat. No. 6,180,806 issued in 2001 to O""Lenick and Imperante disclose glyceryl phosphate quats.
Despite the fact that there was significant patenting of phosphobetaine compounds based upon phosphoric acid salts, phosphorous acids salts, tertiary amine and imidazoline, the technology needed to place a alkyl or acyl moiety into the molecule and make the compounds of the present invention was not appreciated. It was also not until the compounds of the present invention that the concept and technology needed to incorporate the glyceryl group, which adds both to the improved biodegradation, water solubility, humectancy properties and mildness to skin and eyes.
It is the object of the present invention to provide a series of novel ester based phosphobetaine compounds which are environmentally friendly, high foaming, low irritation to eyes and skin, have an inverse cloud point and are substantive to the surface of a fibers, and are very effective emulsifiers, and by virtue of their ester linkage are less persistent in the aquatic environment.
Still another object of the present invention is to provide a series of ester based phosphobetaine compounds that have differing solubilities in water and organic solvents. This is achieved by selection of the phosphate used as a raw material and the amine chosen for preparation of the phosphobetaine.
Application of the compounds of the invention can be from solvent, aqueous dispersion or solution, or applied neat in these processes.
The present invention relates to a series of novel ester based phosphobetaine compounds. The amine group typically will be a quaternized nitrogen. Hence the products are amphoteric, having both an anionic and cationic group present on the same pendant group. The glyceryl group contributes properties to these surfactants resulting in compounds that are outstanding emulsifiers, foaming intensely, are non irritating to eyes and skin and deposits on fiber surfaces and form effective surface modifying finishes. The compounds of the present invention are therefore very well suited to applications in the personal care market.
The compounds of this invention having a pendant amphoteric group, and an ester linkage are represented by the following formula; 
wherein
Rxe2x80x2 is alkyl or alkylene having between 7 and 21 carbon atoms;
a, b and c are each independently integers ranging from 0 to 20, with the proviso that a+b+c be equal to or greater than 1;
R2 is selected from the group consisting of;
alkyl having 7 to 21 carbon atoms and
R3xe2x80x94C(O)xe2x80x94N(H)xe2x80x94(CH2)3xe2x80x94
xe2x80x83R3 is alkyl having 7 to 21 carbon atoms.
The reaction sequence needed to produce the compounds of the present invention is multi-stepped starts with the phosphation of a compound conforming to the following structure;
R1xe2x80x94C(O)Oxe2x80x94(CH2CH2O)axe2x80x94(CH2CH(CH3)O)bxe2x80x94(CH2CH2O)cH with polyphosphoric acid to produce:
R1xe2x80x94C(O)Oxe2x80x94(CH2CH2O)axe2x80x94(CH2CH(CH3)O)bxe2x80x94(CH2CH2O)cP(O)xe2x80x94(OH)2.
The phosphation reagent used in the reaction is polyphosphoric acid, since the reaction with it results in minimal diester. In a preferred embodiment, the reaction is conducted at a mole ratio of 1 (ester) to 0.9 phosphating reagent. This molar excess of ester results in even less diester.
In a subsequent step the ester phosphate is reacted with a either a compound conforming to one of the following structures; 
to give the desired product. Both classes of products are commercially available from a variety of manufacturers including DeGussa and Siltech Corporation.
Preferred Embodiments
In a preferred embodiment R2 alkyl having 7 to 21 carbon atoms.
In a preferred embodiment R2 is R3xe2x80x94C(O)xe2x80x94N(H)xe2x80x94(CH2)3xe2x80x94.
In a preferred embodiment R1 is C7H17.
In a preferred embodiment R1 is C9H19.
In a preferred embodiment R1 is C11H23.
In a preferred embodiment R1 is C13H27.
In a preferred embodiment R1 is C15H31.
In a preferred embodiment R1 is C17H35.
In a preferred embodiment R1 is C19H39.
In a preferred embodiment R1 is C21H43.
In a preferred embodiment R1 is derived from a natural oil including coconut, avocado, olive, castor, borage, soybean, sunflower, safflower, cottonseed, and wheat germ oil.